1. Field of the Invention
This invention pertains to computer input and pointing devices used to control cursor movement on a display. More particularly, this invention pertains to touch-sensitive data input and pointing devices for data input to computers and other devices which benefit from interaction with a user.
2. Prior Art
Input devices for computers are well known in the art. There are several types of input devices including the familiar xe2x80x9cmouse.xe2x80x9d The mouse has become so popular because, when combined with a graphical user interface (GUI), it is so much easier to use than typed keyboard commands. Instead, a cursor is caused to move on a display screen, the cursor being controlled by movements of the mouse being translated into corresponding cursor movements. The mouse has been accepted as a xe2x80x9cuser friendlyxe2x80x9d input device for both experienced and novice computer users. The popularity which the mouse has achieved in the art can be given large credit for fostering the explosive growth of the personal computer industry since a mouse provides a simple means for users to input data to a computer.
While mice are currently the most popular non-keyboard input device, a mouse generally requires a free-rolling surface, i.e. a table top, on which it can operate. Disadvantageously, a mouse is not well suited for use in cramped spaces or with a portable computer, particularly laptop, notebook, sub-notebook, and palmtop computers. In answer to the long existing need for a more convenient input device suitable for both portable and desktop computers, various alternative input devices have been proposed. Such alternative input devices include devices commonly referred to as track balls, track pens, track point devices, as well as various devices which sense the position of a pointing object on a position sensing surface. The devices which sense the position of a pointing object on a sensing surface generally have the advantages of being simple to use, being easily integrated with current computers and other computing devices, reliability, ruggedness, compactness, and the ability to be transported and used in a variety of locations.
Numerous types of input devices utilize a position sensing surface. Examples are provided in the following patent references: U.S. Pat. No. 3,886,311, Rodgers et al. (Writing pen for detecting time varying electrostatic field produced by a writing tablet); U.S. Patent No. 4,672,154, to Rodgers et al. (Cordless stylus which emits a directional electric field from the tip of a conductive pen cartridge sensed by a digitizer tablet having an X-Y coordinate system); U.S. Pat. No. 4,680,430 to Yoshikawa et al. (A tablet-like coordinate detecting apparatus including a resistive film for determining the coordinate position data of a point on a plane indicated by the touch of a finger tip or other load); U.S. Pat. No. 4,103,252 to Bobick (A position sensing tablet with electrodes located on the boundaries of a sensing region which detects a human touch by the change in capacitive charge caused by the touch which varies the time constant of an RC network which is part of an oscillator); U.S. Pat. No. 4,736,191 to Matzke (A touch activated control device comprising individual conductive plates wherein a user""s touch on the dielectric layer overlaying the plates is detected by individually charging and discharging each of the sectors in the plates in a sequential manner to determine the increased capacitance of the sector); U.S. Pat. No. 4,550,221 to Mabusth (A touch sensitive control device which translates touch location to output signals and which includes a substrate that supports first and second interleaved, closely spaced, non-overlapping conducting plates); U.S. Pat. No. 4,639,720 to Rympalski et al. (An electronic sketch pad which contains a graphics input pad having an array of transparent capacitive pixels, the capacitance characteristics of which are changed in response to the passing of a conductive tipped stylus over the surface of the pad); and, European Patent Publication No. 574,213 (A proximity sensor includes a sensor matrix array which senses changes in capacitance between horizontal and vertical conductors connected to the position sensing pad to determine x, y, and z position information).
A particularly useful and advantageous input device is disclosed in U.S. Pat. No. 5,305,017 to Gerpheide. The Gerpheide patent discloses devices and methods which overcome the drawbacks inherent in other devices which utilize a sensing tablet or sensing surface. The devices and methods of the Gerpheide patent include a touch sensitive input pad upon which a user conveniently inputs position information with a finger. In operation, the user""s finger tip is brought in close proximity to the top surface of the position sensing surface of the touch sensitive pad. The device of the Gerpheide patent detects the position of the finger tip in the x and y directions of the touch pad as well as the finger""s proximity in the z direction in relation to the sensing surface. In addition to a finger, the pointing object can be any other conductive object.
The above mentioned input devices are easily distinguished from each other by focusing on a particular characteristic which each device does or does not possess. Specifically, each input device may either be used by moving a stylus across the touchsensitive surface, or a human finger, or both. The input devices of interest are only those which are usable by touching the touch-sensitive surface with a finger.
The different input devices allow for various sensing apparatus of the touch-sensitive devices to detect the finger and translate movement of the finger into corresponding movement of a cursor on a display screen. This patent has within its scope of interest those touchpad-type devices which readily provide tactile feedback to the user, and which control a cursor on a display device. Practically speaking, the greatest feedback occurs when using touchpads and tablets operated by a user""s finger.
One of the advantages of using a touchpad or tablet as an input device is that space is conserved. This means that the touchpad or tablet are not moved around, as is a mouse, in order to manipulate a cursor on a display screen. Instead, a finger is moved across a touch-sensitive surface, while the touchpad or tablet advantageously remains stationary. This characteristic is very important when space constraints are premium, such as on an airplane or a crowded desk.
With the advent of these new touchpad and tablet devices have also come enhancements to make them easier to use and to provide additional benefits over mice and other input devices. In particular, the Gerpheide patent application, Ser. No. 08/413,199, teaches a SYSTEM AND METHOD FOR EXTENDING THE DRAG FUNCTION OF A COMPUTER POINTING DEVICE. This patent application is particularly useful to touchpads and tablets because it makes optimum use of the available touchpad surface area. When a cursor is manipulated to drag an object across a display screen, typically the user cannot complete the operation in a single continuous stroke of a finger. The reason is that although it is common practice to make a small finger movement on a touchpad correspond to a larger cursor movement on a display by magnifying relative motion, available touchpad surface area is still finite. Therefore, in the middle of a drag operation during which the user is maintaining contact with a touchpad, the user is forced to lift the finger. In conventional computer input devices, lifting the finger terminates the drag operation. The user must reselect the object which was being dragged by the cursor, and then continue movement. Depending upon the distance to be moved, this operation might be repeated several times.
The Gerpheide patent advantageously provides new functionality to the touchpad by creating a delay in drag cancellation. Specifically, when dragging an object with a cursor, lifting the finger does not immediately result in termination of drag operation. Instead, a delay in termination provides sufficient time for a user to lift the finger, move it to a new location on the touchpad, and resume dragging the object as if the finger had never been lifted.
Implementation of the drag extend function described above is accomplished by creating regions on the touchpad surface which provide new functionality. For example, moving a finger into an appropriate region activates a desired function. With drag extend, the most logical location for a region which can activate the function is the perimeter of a touchpad. This is because the user""s finger is going to reach the edge of the touchpad. By creating a border region around the entire touchpad perimeter, the drag extend function can be activated while dragging in any direction. It should be apparent from the explanation above that endowing a border region with extended functions such as drag extend can be advantageous for the user.
A problem which is not readily apparent from the description given above is that a user is not always aware of the location of their finger on the touchpad. A user is manipulating the position of a cursor on a display screen, and therefore is concentrating on watching the display and not the touchpad. The problem arises when a user wants to use, for example, the drag extend function. The surface of a touchpad is typically uniformly smooth to the perception of human touch. Typically, there is no tactile indication to assist a user in determining whether a finger is within the border region or not. Consequently, when the user executing the drag operation lifts the finger from the touchpad, the drag function might terminate. In essence, no way is readily provided for a user to know when a finger has entered the border region.
One attempt at a solution to this problem of inadequate tactile feedback is provided by Logan et al. in U.S. Pat. No. 5,327,161. Generally, the Logan patent apparently addresses the issues of replacing an ordinary mouse with a touchpad type device. Specifically, the patent teaches providing extended functionality to a touchpad by placing touch-sensitive sensor strips on a physically raised outer perimeter or bevel around the touchpad, but not actually on the touchpad surface. When a finger comes in contact with the touch-sensitive strips, extended functionality is provided to the user.
One of the several disadvantages of the Logan patent is that construction of the touchpad is needlessly complicated. Specifically, Logan requires a raised bevelled edge to be created around the touchpad perimeter to provide the physical tactile feedback to the user that an edge of the touchpad has been reached. The touch-sensitive strips are formed independent of the touchpad material, and they require additional circuitry, sensors, and a coordinating processor to determine when the touchpad surface and the touch-sensitive strips are being activated simultaneously.
Another disadvantage is that Logan does not teach how nearing the perimeter of the touchpad can be useful. Instead, Logan only provides tactile feedback when the user actually strikes the bevelled edges of the touchpad. The user is given no tactile warning that an edge is approaching. Illustrated in FIG. 1 as a representation of a computer system 16 to which is attached a mouse 10 through interface 18, wherein the mouse acts as a cursor locator input device. The movement of the mouse 10 is translated into movement of a cursor on a display 20 coupled to the computer 16 in real time. In many cases, it is desirable that any input device to be used with the computer 16 be compatible therewith. Alternatively, a cursor locating device can interface directly with the computer 16, for example via an operating system or some other technique which does not require a mouse driver.
In order to be compatible with the computer 16, any input device must provide xe2x80x9cclickxe2x80x9d, xe2x80x9cdragxe2x80x9d and xe2x80x9cgesturexe2x80x9d functions which can also be provided by the mouse 10. The click function entails depressing and releasing one of the mouse buttons 12 or 14. The click function may entail single, double, triple or even half clicks. For example, a one and a half click is where the user uses a finger to press down on a button or surface, raises the finger to release, then presses down and holds the button or surface with the finger again. The drag function entails moving the cursor over text or an object on the display 20, depressing a mouse button 12 or 14, keeping the mouse button depressed while xe2x80x9cdraggingxe2x80x9d the text or object to a new location on the display 20, and releasing the mouse button to position the text or object on the new location on the display 20. Finally, gestures are symbols or other figures created by tracing alphanumeric characters on the touchpad.
Also represented in FIG. 1 is a touch-sensitive positioning device, generally referred to at 26, which includes a position sensing surface 22 and a pointing object 24. Early versions of these touch-sensitive touch-pad type devices included mechanical buttons, such as those shown at 28 and 30 which provide the functions of mouse buttons 12 and 14, respectively.
However, advancements have made it possible to have a touch 15 sensitive device which no longer requires mechanical switch buttons to carry out the click function. Instead, the touchsensitive devices require a user to simply lift a finger and tap once, twice, three times or with half-taps on the touch-sensitive surface. The tapping motion is detectable by the touch-sensitive circuitry which informs the driver or application software of the input action.
FIG. 2A is a schematic side elevational view of a touchpad input device 40 illustrating a touch-sensitive bezel 42 of the system taught in U.S. Pat. No. 5,327,161 by Logan et al. Logan has significant disadvantages which are overcome by the present invention. However, to understand the improvements, it is necessary to have a little background in order to illustrate them.
As shown, the touch-sensitive surface is recessed 44 down into a touchpad 40. At the borders of the touchpad 40 are four beveled edges 42 to which is attached a piezoelectric or some similar sensor device 46. When a user""s finger presses against the beveled surface 42, the attached sensor 46 registers the contact and signals activation of a computer input function. This view also shows the mechanical switch 48 below the touch-sensitive touchpad 40 which is activated by pressure on the surface 50 above. The touch-sensitive surface 50 has no other features, other than a dotted line 52 shown in FIG. 2B.
FIG. 2B is a top view of the touchpad 40 shown in FIG. 2A. The notable feature is the dotted line 52 defining a perimeter of the touchpad surface 50 already mentioned. With this complete view, an illustration of what Logan describes as continued cursor movement can now be explained.
The beveled edges 42, or alternatively the dotted line 52, can indicate to the user when continued cursor movement is activated. This occurs in Logan when a finger presses down on the touchpad surface 50 within the dotted line 52, selects an object on a display screen, and closes the mechanical switch 48. When the user moves the finger to an edge 42 until it touches, or alternatively crosses the dotted line 52, the continued cursor movement mode is activated, and the cursor continues to move in the same direction it was originally moving until the finger is removed from the beveled edge 42 or lifted from the touchpad surface 50.
The method and apparatus has several shortcomings, some of which are described below. First, the touchpad 40 uses a mechanical switch 48 to indicate that a drag function is being activated. A mechanical switch 48 is inherently prone to failure because the physical components can become contaminated and the switch may fail due to wear.
Second, there is no warning to the user that a finger is approaching an edge 42 of the touchpad 40. Consequently, the user may not wish to activate the continued cursor movement mode, but may do so inadvertently.
Third, the sensors 46 on the beveled edges 42 are not part of the touchpad sensor array. Therefore they require additional circuitry to decode signals received therefrom.
Fourth, the dotted line 52 around the perimeter of the touchpad surface 50 is only a visual indicator for where the continued cursor movement mode begins. The user is thus required to view the touchpad 40 anytime confirmation is required of the present location of the finger on the touchpad surface 50. This slows down a user of the touchpad 40.
The drawbacks of Logan et al. include insufficient tactile feedback indicating when a special function has been activated. They also include the additional circuitry which is required in a system which does not integrate sensing of movement into a perimeter of the touch pad with the already available touchpad circuitry.
Thus, it would be an advance in the art to provide a touch-sensitive finger actuable touchpad or tablet which provides tactile feedback to the user who is manipulating a cursor on a display screen, when a finger has passed into a special functions region of the surface, and without requiring additional circuitry or modification to existing designs.
In view of the above described state of the art, the present invention seeks to realize the following objects and advantages.
It is a primary object of the present invention to provide a method and apparatus for providing tactile feedback for an electronic touch-sensitive computer input and cursor manipulation device.
It is another object of this invention to provide a method and apparatus for providing tactile feedback for electronic touch-sensitive computer input devices which is particularly adapted for use with a touch-sensitive touchpad or tablet type computer input and pointing devices.
It is yet another object of this invention to provide a method and apparatus for providing tactile feedback for electronic touch-sensitive computer input devices which can operate with a user""s finger as the only pointing object.
It is still a further object to provide a method and apparatus for providing tactile warning to a user that a finger moving on the touchpad surface is approaching an edge, but before reaching the edge.
These and other objects are realized in a method and apparatus for providing a tactile feedback response to a user moving their finger across the touch-sensitive surface of a touchpad or tablet. Different regions of the touch-sensitive surface are differentiated from each other by providing a different human perceptible textural surfaces within the regions. A different texture provides immediate tactile feedback to the user through the finger making contact with the touchpad. Increased functionality is important because it solves problems which are inherent to the small touchpad surfaces used as computer input devices. Particularly, it is a problem to drag an object from one side of a display to another without repeatedly raising a finger to repeat the dragging motion because of the limited surface area of the touchpad surface. Providing increased functionality such as a drag extend function solves the movement problem. The present invention then solves the problem of conveying to the user through touch, information about the location of the finger without having to look away from the display screen, thereby facilitating input and cursor manipulation for a computer. The apparatus of the present invention preferably includes an electronic touch-sensitive touchpad or tablet which can be actuated by a human finger, an associated processing device such as a computer, and a display screen whereon a cursor being manipulated by the touchpad is displayed.
The method of the present invention includes the step of creating a touchpad having regions of different textures. This is accomplished by either manufacturing the touchpad surface with the different textures, or adhering differently textured materials to the touchpad surface after manufacture. It is also conceivable that the different regions could be manufactured separately, and then mounted together such that there is a generally continuous touchpad surface over which the user""s finger can slide. However, this approach is prohibitively more expensive and unnecessary.